1. Field of the Invention
This invention relates to a stable aqueous fertilizer composition concentrate comprising potassium and a mixture of guar gum and xanthan gum as a stabilizing agent.
2. Technology Description
It is known that aqueous fertilizer compositions in a fluid form present several advantages compared with fertilizer composition in a solid form.
The preparation of such liquid aqueous compositions avoids granulating and drying steps and obviates other drawbacks such as caking or dust formation.
These aqueous fertilizer compositions are currently made in a liquid form as solution and/or as suspension fertilizers. In solution, the fertilizers are dissolved in water and, in suspension, the fertilizers are still present as a solid phase and have to remain as a stable suspension in water.
However, a serious disadvantage of liquid fertilizer resides in the limited solubility of most of the various salts comprising the nutrients themselves, thereby making it difficult to obtain product concentrates.
Attempts have been made to prepare aqueous suspensions having a nutrient content higher than that of solutions. However, the storage stability is insufficient, and to obtain fertilizer suspensions that are stable during storage, it is known to add to these suspensions various suspending agents. These suspending agents can be swelling clays such as bentonite and attapulgite as described in U.S. Pat. Nos. 3,109,729 and 3,096,170 or starches, gums and carboxymethyl cellulose as described in U.S. Pat. No. 3,234,005.
These most promising suspending agent improvements, however, have proven to be insufficient for aqueous fertilizer compositions comprising potassium.
Potassium is an essential nutrient used on many crops in fairly large amounts. As a nutrient for fluid formulations, potassium is difficult to manage due to its high bulk density. Useful potassium compounds have a tendency to settle or to salt out of solution. This is particularly true for potassium sulfate or sulfate of potash, which is a preferred potassium and sulfur source for chloride and salt sensitive crops.
Moreover, the suspensions of the prior art when used in drip irrigation systems, clog the apertures or holes of the lines or hoses because of the presence of clay suspending agent.
A principal object of this invention is to provide an aqueous fertilizer composition concentrate comprising potassium, i) which is stable upon storage for several months; ii) that can be shipped without settling; iii) that has a high content of nutrients; and iv) that can be more particularly used in drip irrigation systems without clogging the apertures or holes of the lines or hoses.